Core Diffusion Research Articles

Few group cross sections generation using MCU-PTR and Serpent for diffusion calculation of light water research reactor

Different methods of generating homogenized few-group cross sections using continuous energy Monte Carlo codes MCU-PTR and Serpent 2.1.27 for full core diffusion calculation of small-size light water reactor were studied. Few-group cross sections were used in core diffusion nodal simulator TIGRIS for the calculation of the simplified cores with fuel of CROCUS reactor and IRT-type reactor in light water reflector. Special attention is paid to the impact of diffusion coefficients on the results of diffusion calculation. Three different ways of diffusion coefficient generation were compared: usual “out-scatter” approximation, using of the hydrogen transport correction curve and migration area method.

Selective recovery of mercury from high mercury-containing smelting wastes using an iodide solution system.

The mercury resources recovery and safe disposal of mercury-containing waste is an urgent problem. In this study, a new method using an iodide solution system was proposed to selectively recover mercury from high mercury-containing smelting wastes. The mercury leaching efficiency, yields, leaching kinetics and thermodynamics were researched. The major factors which affect mercury leaching efficiency including iodide concentration, oxidant, pH and temperature were evaluated. Over 97% and 93% of mercury can be efficiently leached from wastewater treatment sludge (W-S) and acid sludge (A-S). After leaching, the mercury concentration during leaching toxicity test is under the limits set for hazardous waste. Additionally, the electrolytic technology can efficiently recover mercury from leachate in the form of elemental mercury, and the leachate after electrolytic can be reused for mercury leaching. The mercury leaching kinetics follows the shrinking core diffusion model and is controlled by solid product diffusion. The mechanism research shows the leaching efficiency was strongly dependent on the distribution of mercury species in smelting waste. The consequence on mercury leaching and recovery could provide nonferrous smelters with a practical and yet easy-to-adopt perspective to reduce the risk of mercury contamination and selectively recover mercury resources from mercury-containing smelting wastes.

Trading off between dynamic strain aging and substructure evolution in κ-carbide-free lightweight steel at room temperature

The previous proposed models to describe the room temperature dynamic strain aging of twinning-induced-plasticity steels appear to be theoretically invalid in the case of lightweight grades. The proposed theory in the present work accentuates the high capability of the experimented dilute solid solution in progressive formation and refinement of the cell structures. The higher dislocation population in the cell-walls in comparison to that of cell-interiors is viable enough to increase the stress assisted drift and stimulate the sub-boundaries preferred sites to accommodate the solutes. The short-range dislocation core diffusion enables the cell-walls to assist the strain aging to occur.

Effect of Graphitic Carbon Nitride Nanosheets Addition on the Microstructure and Mechanical Properties of Sn-3.5Ag-0.5Cu Solder Alloy

The microstructure and mechanical properties of Sn-3.5Ag-0.5Cu (SAC355) solder alloy reinforced with different amounts of graphitic carbon nitride nanosheets (GCNNs) are assessed. The as-synthesized GCNNs were examined by a scanning electron microscope and X-ray diffraction techniques. A set of composite solders were fabricated by adding GCNNs with different concentrations (0 wt.%, 0.25 wt.%, 0.5 wt.%, and 1.0 wt.%) to SAC355 solder alloy. After a solution heat treatment, samples were immediately aged at temperatures ranging from 343 K to 403 K for 2 h followed by water quenching at 273 K. The mechanical properties of the composite solders were assessed using the indentation hardness test. The experimental results showed that the minimum creep rate values estimated from hardness data increased progressively with increasing weight percentage of GCNNs and/or aging temperature. The homogeneous distribution of GCNNs in the composite solders allows microscopic defects such as cracks to develop throughout the solders leading to higher creep rate values. The calculated values of the stress exponent and the activation energy for the creep process indicated that the creep rate controlling process depends on dislocation core diffusion in the tin matrix.

Measurement of optical fiber parameters and thermal core diffusion characteristics by digital image processing.

The simultaneous measurement of the numerical aperture (NA) and mode field diameter (MFD) of single-mode fibers was performed on several commercial fibers by means of digital image processing of the output light projected into a screen. In addition, the changes induced by core diffusion in an ultra-high (UH) NA fiber at several heat depositions from a CO2 laser source were measured. The measurement method was demonstrated to be useful to monitor the adiabaticity of this process, by taking the product of the NA and MFD to verify if it remains constant. The method provides a cheap alternative to measure these optical fiber parameters by using simple optomechanical elements and a readily available smartphone camera, and it can be easily implemented in the laboratory.

Time-resolved, defect-hosted, trace element mobility in deformed Witwatersrand pyrite

The Pb isotopic composition of rocks is widely used to constrain the sources and mobility of melts and hydrothermal fluids in the Earth's crust. In many cases, the Pb isotopic composition appears to represent mixing of multiple Pb reservoirs. However, the nature, scale and mechanisms responsible for isotopic mixing are not well known. Additionally, the trace element composition of sulphide minerals are routinely used in ore deposit research, mineral exploration and environmental studies, though little is known about element mobility in sulphides during metamorphism and deformation. To investigate the mechanisms of trace element mobility in a deformed Witwatersrand pyrite (FeS2), we have combined electron backscatter diffraction (EBSD) and atom probe microscopy (APM). The results indicate that the pyrite microstructural features record widely different Pb isotopic compositions, covering the entire range of previously published sulphide Pb compositions from the Witwatersrand basin. We show that entangled dislocations record enhanced Pb, Sb, Ni, Tl and Cu composition likely due to entrapment and short-circuit diffusion in dislocation cores. These dislocations preserve the Pb isotopic composition of the pyrite at the time of growth (∼3 Ga) and show that dislocation intersections, likely to be common in deforming minerals, limit trace element mobility. In contrast, Pb, As, Ni, Co, Sb and Bi decorate a high-angle grain boundary which formed soon after crystallisation by sub-grain rotation recrystallization. Pb isotopic composition within this boundary indicates the addition of externally-derived Pb and trace elements during greenschist metamorphism at ∼2 Ga. Our results show that discrete Pb reservoirs are nanometric in scale, and illustrate that grain boundaries may remain open systems for trace element mobility over 1 billion years after their formation.

Validation of DRAGON4/DONJON4 simulation methodology for a typical MNSR by calculating reactivity feedback coefficient and neutron flux

Abstract The MNSR is a pool type research reactor, which is difficult to model because of the importance of neutron leakage. The aim of this study is to evaluate a 2-D transport model for the reactor compatible with the latest release of the DRAGON code and 3-D diffusion of the DONJON code. DRAGON code is then used to generate the group macroscopic cross sections needed for full core diffusion calculations. The diffusion DONJON code, is then used to compute the effective multiplication factor (keff), the feedback reactivity coefficients and neutron flux which account for variation in fuel and moderator temperatures as well as the void coefficient have been calculated using the DRAGON and DONJON codes for the MNSR research reactor. The cross sections of all the reactor components at different temperatures were generated using the DRAGON code. These group constants were used then in the DONJON code to calculate the multiplication factor and the neutron spectrum at different water and fuel temperatures using 69 energy groups. Only one parameter was changed where all other parameters were kept constant. Finally, Good agreements between the calculated and measured have been obtained for every of the feedback reactivity coefficients and neutron flux.

CO2-EOR mechanisms in huff-n-puff operations in shale oil reservoirs based on history matching results

Improved Oil Recovery (IOR) techniques in Unconventional Liquids Rich Reservoirs (ULR) are still a new concept because there is no commercial project for any IOR technique so far. Carbon dioxide (CO2) based EOR technique has been effectively applied to improve oil recovery in the tight formations of conventional reservoirs. Extending this approach to unconventional formations has been extensively investigated over the last decade because CO2 has unique properties which make it the first option of EOR methods to be tried. However, the applications and mechanisms for CO2-EOR in unconventional reservoirs would not necessarily be the same as in conventional reservoirs due to the complex and poor-quality properties of these plays.Since the first CO2-EOR huff-n-puff project was conducted in conventional reservoirs in Trinidad and Tobago in 1984, more than 130 additional projects have been put in operation around the world, mainly located in USA, Turkey, and Trinidad and Tobago. In this study, we combined Production Data Analysis (PDA) for the production data of these projects with numerical simulation methods to produce one typical graph accounts for the main mechanisms controlling CO2-EOR performance in conventional reservoirs. On the other hand, we have couple of CO2-EOR huff-n-puff pilot tests conducted in Bakken formation between 2008 and 2016. Two engineering-reversed approaches have been integrated to produce a unique type curve for the performance of CO2-EOR huff-n-puff process in shale oil reservoirs. Firstly, a numerical simulation study was conducted to upscale the reported experimental-studies outcomes to the field conditions. As a result, different forward diagnostic plots have been generated from different combinations for CO2 physical mechanisms with different shale-reservoirs conditions. Secondly, different backward diagnostic plots have been produced from the history match with CO2 performances in fields’ pilots performed in some portions of Bakken formation located in North Dakota and Montana. Finally, fitting the backward with the forward diagnostic plots was used to produce another unique type curve to represent CO2-EOR performance in shale oil reservoirs. This study found that the delayed response in the incremental oil production resulted from CO2 injection in shale reservoirs is mainly function of CO2 molecular diffusion mechanism. On the other hand, the CO2 diffusion mechanism has approximately no effect on CO2-EOR performance in conventional reservoirs which have a quick response to CO2 injection. This finding is very well consistent with the experimental reports regarding the role of diffusion in conventional cores versus shale cores. In addition, this study found that kinetics of oil recovery process in productive areas and CO2-diffusivity level are the keys to perform a successful CO2-EOR project in shale formations. This paper provides a thorough idea about how CO2-EOR performance is different in the field scale of conventional reservoirs versus shale formations.

Leakage correction in group-constant generation for pebble-bed HTGRs

Neutronics design of commercial reactors currently utilizes a procedure linking lattice physics and core physics calculations together, where broad-group constants are generated by fine-group lattice calculations and are then used by downstream whole-core diffusion calculations. Among this procedure, the leakage effect in group-constant generation contributes a non-negligible source of errors. In pebble-bed high temperature gas-cooled reactors (HTGRs), this effect becomes even important because the neutron diffusion length is relatively large compared with the size of pebble lattice. Traditional neutronics analysis codes for pebble-bed HTGRs need repeatedly re-call lattice calculations with the leakage information obtained from core diffusion calculations. In this paper, existing methods for leakage correction are reviewed, and a new method is proposed to correct broad-group constants by using buckled fine-group spectrum. The new method eliminates the need of online coupling between lattice physics and core physics calculations, and thus makes it possible to use the tabular group-constant library as is done in light water reactors (LWRs). Numerical tests show that the proposed method are promising for leakage correction in pebble-bed HTGR analyses.

Development and validation of uncertainty neutron transport calculations at an industrial scale

Evaluating uncertainties on nuclear parameters such as reactivity is a major issue for conception of nuclear reactors. These uncertainties mainly come from the lack of knowledge on nuclear and technological data. Today, the common method used to propagate nuclear data uncertainties is Total Monte Carlo [1] but this method suffers from a long time calculation. Moreover, it requires as many calculations as uncertainties sought. An other method for the propagation of the nuclear data uncertainties consists in using the standard perturbation theory (SPT) to calculate reactivity sensitivity to the desire nuclear data. In such a method, sensitivities are combined with a priori nuclear data covariance matrices such as the COMAC set developed by CEA. The goal of this work is to calculate sensitivites by SPT with the full core diffusion code CRONOS2 for propagation uncertainties at the core level. In this study, COMAC nuclear data uncertainties have been propagated on the BEAVRS benchmark using a two-step APOLLO2/CRONOS2 scheme, where APOLLO2 is the lattice code used to resolve Boltzmann equation within assemblies using a high number of energy groups, and CRONOS2 is the code resolving the 3D full core diffusion equation using only four energy groups. A module implementing the SPT already exists in the APOLLO2 code but computational cost would be too expensive in 3D on the whole core. Consequently, an equivalent procedure has been created in CRONOS2 code to allow full-core uncertainty propagation. The main interest of this procedure is to compute sensitivities on reactivity within a reduced turnaround time for a 3D modeled core, even after fuel depletion. In addition, it allows access to all sensitivites by isotope, reaction and energy group in a single calculation. Reactivity sensitivities calculated by this procedure with four energy groups are compared to reference sensitivities calculated by the iterated fission probability (IFP) method in Monte Carlo code. For the purpose of the tests, dedicated covariance matrix have been created by condensation from 49 to 4 groups of the COMAC matrix. In conclusion, sensitivities calculated by CRONOS2 agree with the sensitivities calculated by the IFP method, which validates the calculation procedure, allowing analysis to be done quickly. In addition, reactivity uncertainty calculated by this method is close to values found for this type of reactor.

Enhancing creep resistance of SnBi solder alloy with non-reactive nano fillers: A study using nanoindentation

With excellent performance in mechanical strength and hardness, low melting point solder alloys have been identified as a promising lead-free alternative for microelectronic industry. However, the application of such alloys is hindered because of the serious creep deformation when electronic devices are inevitably heated up during operation or even at room temperature. In this study, non-reactive Al2O3 nano particles is explored as an option to enhance the creep resistance of eutectic SnBi alloy that has a melting temperature of 139 °C. Eutectic SnBi was mixed with nano Al2O3 particles for up to 4 wt%. Nanoindentation testing protocol for the creep properties measurement is used in this study. Core diffusion controlled dislocation climb is found to be the creep mechanism for the composite alloy. Other mechanical properties including elastic modulus and hardness are also evaluated and related to the microstructure evolvement of the nanocomposite alloy at various filler loadings. This work also compares the effectiveness of non-reactive fillers with the reactive fillers on enhancing the creep resistance of SnBi alloy. Suitable filler candidates for the best mechanical performance of SnBi composite alloys are recommended.

Non-Fickian mass transfer in swelling polymeric non-porous membranes

The aim of this contribution is to formulate a model that investigates the probable occurrence of non-Fickian behavior of mass transport in a viscoelastic polymeric non-porous membrane that swells. Using both continuum mechanics and non-equilibrium thermodynamics approaches, we derive a set of coupled time evolution equations that explicitly incorporate the stress-diffusion mutual interaction. In this 3-D macroscopic model, the trace Π (i.e. the polymer elastic osmotic pressure) and traceless [σp] parts of the polymer second order stress tensor σp serve as the structural independent state variables. In the one dimensional setting, scaling analysis leads to the emergence of three relevant groups of physical parameters namely the core and surface diffusion Deborah numbers De and Deb and a diffusion-stress coupling constant E0 whose effects are examined for both sorption and permeation unsteady processes. We have solved numerically the 1-D governing equations expressed in the material coordinates and obtained profiles for the solvent concentration, non-Fickian diffusion mass flux, stress distribution, swelling, mass-uptake and stress-uptake. The model is capable of predicting a wide range of non-Fickian behaviors, including the two-stage and overshoot cases; and the confrontation with experimental data selected from the literature shows a good agreement.

Critical evaluation of creep behavior of Sn-Ag-Cu solder alloys over wide range of temperatures

A critical survey of the current literature on creep behavior of Pb-free Sn based Sn-Ag-Cu (SAC) alloys show that there is considerable discrepancy in the creep parameters, such as activation energy, Qc, and stress exponent, n. Accordingly, this study addresses the underlying reasons for such variability in the existing data by studying the creep behavior in compression of two most commonly used SAC alloys, namely Sn-1wt.%Ag-0.5wt.%Cu and Sn-3wt.% Ag-0.5wt.% Cu, over wide range of temperatures, from 60 to 200°C, and stresses from 7 to 14MPa. Analysis of microstructure of SAC alloys reveals that both temperature and stress have pronounced effects on coarsening of precipitates during creep. The steady state strain rate increases with both temperature and stress as well as with decrease in Ag content of the alloys. Irrespective of the composition, SAC alloys show a transition in the creep behavior around 150°C, with Qc and n changing from 55kJ/mol and 7, respectively, at low temperatures to 100kJ/mol and 5, respectively, at higher temperatures. Such a simultaneous change in both Qc and n suggests that creep mechanism in SAC alloys is dislocation climb controlled by the core diffusion at low temperatures and the lattice diffusion at high temperatures.

High P–T experiments and first principles calculations of the diffusion of Si and Cr in liquid iron

Chemical diffusion rates of Si and Cr in liquid iron have been measured over the P–T range of 1–18GPa and 1873–2428K. The experiments were performed using a multi-anvil apparatus with diffusion couples comprised of pure iron and iron alloy placed end to end in a vertical orientation. In order to extend our dataset to the Earth’s core–mantle boundary and to compare experimental data with theoretical diffusion rates calculated under laboratory-accessible conditions, we have also performed first principles molecular dynamic simulations (FP-MD) and calculated self-diffusion coefficients and activation parameters for Si, Cr, and Fe diffusion in liquid Fe, Fe0.92Si0.08 and Fe0.92Cr0.08 compositions over the P–T range of 1bar–135GPa and 2200–5500K. Over the entire range of pressures and temperatures studied using both methods, diffusion coefficients are described well using an exponential function of the homologous temperature relation, D=Dhexp(−gTh), where Th=Tm/T, Tm is the melting temperature at the pressure of interest and g and Dh are constants. Our findings indicate constant diffusivities of approximately 4×10−9m2s−1 for Si and Cr and 5×10−9m2s−1 for Fe along the melting curve from ambient to core pressures in all liquid compositions studied, with an increase of ∼0.8logunits at T=2Tm. Differences between experimental data and computational results are less than 0.1logunits. Structural properties of liquid iron alloys analyzed using partial radial distribution functions (RDFs) show the average distance between two Fe atoms, rFe–Fe, is identical to that of rFe–Si and rFe–Cr over the entire P–T range of study, which supports that the diffusion of Si and Cr (and thus likely other species of similar atomic radii) occurs via direct substitution with Fe. Diffusion coefficients and interatomic distances used to calculate liquid viscosities via the Stokes–Einstein relation yield constant viscosity along the melting curve of ∼6mPas for liquid Fe, ∼7mPas for liquid Fe0.92Cr0.08, and ∼8mPas for liquid Fe0.92Si0.08, with a decrease of ∼0.8logunits at T=2Tm. The data can also be reproduced within <10% using the Arrhenian model with derivatives of the activation parameters determined over a very wide range of P–T conditions. Verification of a homologous temperature dependence of diffusion in liquid metals, as well as the excellent agreement between experimental results and FP-MD simulations, provides a new and simple framework for interpreting and modeling mass transport processes of liquid iron alloys in all planetary bodies regardless of size. Our results are used to evaluate the kinetics of metal–silicate chemical equilibration during core formation and diffusivity contrasts across a solid–liquid metal interface, i.e. at the inner core boundary.

Investigation of microstructure and mechanical properties of Sn-xCu solder alloys

The microstructure and mechanical properties of five binary pre-aged Sn-Cu alloys with varying Cu contents were investigated. The Cu compositions examined varied from 1 wt% to 5 wt%. Serial aging heat treatment processes were performed at 373, 393, 413 and 433 K with a holding time of 2 h at each temperature. The microstructural characteristics of the tested alloys have been investigated using scanning electron microscope (SEM) and X-rays diffraction (XRD). Typical indentation creep curves were derived from hardness values. The minimum creep rate is increased as the Cu content increased up to 4 wt%, but above this level the trend is reversed. Moreover, increasing aging temperature resulted in an increase in the minimum creep rate for the all tested alloys. The mean values of energy activating the creep process are in agreement with that quoted for dislocation core diffusion mechanism.

Creep behavior of Sn–Bi solder alloys at elevated temperatures studied by nanoindentation

The creep mechanisms of eutectic Sn–Bi alloy were evaluated with indentation constant strain rate (CSR) method at elevated temperatures. The activation energy (Q) and creep stress exponent (n) of eutectic Sn–Bi alloy and other alloy compositions were measured in the temperature range from 25 to 100 °C. Prior to this, the indentation CSR testing protocol for evaluation of Q and n was validated through evaluating the pure Sn (grain size >100 µm) at various temperatures. The creep mechanism of large grain-sized Sn was found to be dislocation climb controlled by core diffusion in bulk. Dislocation climb though core diffusion and power-law breakdown were suggested to be the deformation mechanism for pure Bi and Sn–3%Bi alloy, respectively. For the two-phased eutectic Sn–Bi alloy, the creep mechanism was found to be strain rate and temperature dependent. Individual constituent phases were found to take turns to dominate the creep rate at different strain rates.

Dynamic oxygen storage modeling in a three-way catalyst for natural gas engines: A dual-site and shrinking-core diffusion approach

A dual-site oxygen storage model was developed to predict the dynamic oxygen storage on a Pd/Rh/CeZrOx TWC catalyst. Two oxygen storage sites (surface and sub-surface) were used to describe two distinct regimes of the oxygen storage process. A shrinking core diffusion model was applied on the sub-surface site to predict slow oxygen storage and depletion. It is found that water gas shift and steam reforming reactions play significant roles in determining the oxygen storage capacity (OSC) and they were included in the model. A methodology of OSC measurement was designed to quantify the OSC with distinct reductants over a temperature window of 250°C to 650°C for model development. The amount of OSC with different reductants were compared. The reducibility of the reductants on OSC decreased in the order of H2>CO>CH4. The amount of OSC showed a slight temperature dependency when using H2, followed by CO and CH4 in the temperature from 250°C to 450°C. However, similar amount of OSC was observed when the temperature was above 450°C regardless of the reductants. With the dual-site OSC model, the dynamic oxygen storage capacities with various reductants could be correctly predicted.

Effect of creep on the Bauschinger effect in a polycrystalline austenitic stainless steel

A combined thermodynamic/kinetic approach is adopted to derive the climb-controlled recovery of dislocation junctions on individual slip planes in a material during creep when dislocation core diffusion is the rate controlling kinetic process. The model is used in an integrated multi-scale crystal plasticity/creep self-consistent framework to evaluate the effect of creep pre-strain on the Bauschinger effect in a polycrystalline austenitic stainless steel. The model predictions are in good agreement with experimental findings of the effect of tensile creep on the subsequent low temperature response in tension and compression and on the development of residual stresses determined from neutron diffraction studies.

Examination of rate-controlling mechanisms for plastic deformation of pearlitic steel at low homologous temperatures

The rate-controlling mechanisms of plastic deformation of pearlitic steel before and after cold drawing at low homologous temperatures (T/Tm) were explored because cold-drawn pearlitic steel is an important structural material that requires long-term sustainability at low T/Tm. Both the undrawn and the cold-drawn pearlitic steels were deformed plastically under constant loads at low T/Tm of 0.25–0.30. The strain rate-stress data were analyzed in terms of a power law model based on low temperature dislocation climb, a lattice friction controlled plasticity model, and an obstacle controlled plasticity model. The first two models were inadequate to explain low T/Tm plastic deformation of the present steels: (a) much higher activation energy than that for core diffusion resulted from the low temperature dislocation climb model, and (b) athermal stress comparable to that for pure α-Fe was estimated from the lattice friction controlled plasticity model, so the role of cementite on athermal stress in pearlite was unexplainable. By contrast, the obstacle controlled plasticity model estimated activation energy on the same order as that for overcoming forest dislocations which were regarded as the main obstacles in the present steels, as evidenced by microstructural observation. In addition, this model not only gave an estimate of the athermal stress for the present pearlitic steel that was higher than that of pure α-Fe (reflecting the effect of cementite on athermal stress), but also provided an estimate of the athermal stress of the cold-drawn steel that was higher than that of the undrawn steel (reflecting the effect of pre-existing dislocations caused by cold-drawing in the former). Therefore, it is probable that low T/Tm plastic deformation of the present pearlitic steels is rate-controlled by dislocation glide overcoming forest dislocations generated by low T/Tm deformation and/or by cold drawing.

Bioleaching and selective biorecovery of zinc from zinc metallurgical leach residues from the Três Marias zinc plant (Minas Gerais, Brazil)

BACKGROUND Gradual depletion of high-grade ores for heavy metals has encouraged industries to search for alternative methods to recover metals. Wastes generated from metallurgical industries can be used as a secondary resource as it contains high concentrations of metals. RESULTS The bioleaching kinetics and biorecovery of zinc from Zn-plant leach residues (ZLR), collected from a currently operating Zn-plant in Tres Marias (Minas Gerais, Brazil) were investigated using sulfuric acid producing Acidithiobacillus thiooxidans (A. thiooxidans). Response surface methodology (RSM) with full factorial central composite design (CCD) was applied to optimize Zn bioleaching by A. thiooxidans. The experiments were performed by varying the initial elemental sulfur concentration (5–30 g L−1), pulp density (5–50 g L−1) and initial pH (3.0–4.0 pH units). More than 75% of Zn was extracted from ZLR by A. thiooxidans under optimized conditions (sulfur concentration 25.1 g L−1, pulp density 21.5 g L−1 and initial pH 3.3). The leaching efficiencies of culture supernatant (biogenic sulfuric acid) and chemical sulfuric acid were compared to understand the leaching kinetics. The Zn leaching kinetics of ZLR followed the shrinking core diffusion model. Zn was selectively recovered from the Fe-rich acidic bioleachate by biogenic sulfide precipitation. Fe was first removed (more than 85% of total Fe in the leachate) by adjusting the initial pH to 5.0, followed by selective Zn biorecovery. CONCLUSIONS Zn (>95%) was selectively recovered from Fe-depleted ZLR by biogenic sulfides (with 1:1, Zn:biogenic sulfide mass ratio). Biohydrometallurgy can be a potential alternative resource recovery strategy for the selective recovery of Zn from ZLR. © 2016 Society of Chemical Industry